JavaScript for Blockchain Developers.

https://cll-devrel.gitbook.io/javascript-for-blockchain-master-class/decentralized-news-service-contract

If this looks too tricky for you, check out: https://docs.chain.link/quickstarts/deploy-your-first-contract

Day 1: Build a simple decentralized news aggregator service

Following Richard's tutorial, the following was created:

• contracts verified and deployed on sepolia testnet

• Using Chainlink functions to get the latest news from hackernews api, store the story on the blockchain, and display the stories on a webpage.

Todo

• Create a contract that uses Chainlink functions to get the latest news from hackernews api
• Store the story on the blockchain
• Display the stories on a webpage

Steps to run the project:

The contract is good to go and hooked up to Chainlink Functions Subscriber. To deploy and set up your Functions, you need to:

• Compile and deploy the contract on a testnet (this is on Sepolia)

• Create and fund a Chainlink Functions Subscription

• Add your deployed contract address to your subscription as a "Consumer"

• Add your subscription ID to the contract

• Run the sendRequest function on the contract to get the latest news from Hackernews and save it to the blockchain

• Call the getAllArticles function to get the latest news from the blockchain

  function getAllArticles() public view returns (string[] memory) {
          string[] memory allArticles = new string[](articles.length);
          for (uint i = 0; i < articles.length; i++) {
              allArticles[i] = string(articles[i].url);
          }
          return allArticles;
      }

• in /src/pages/index.astro you can display the stories on a webpage

  async function fetchOGData(url) {
  try {
    const response = await fetch(url);
    const html = await response.text();
    const dom = new JSDOM(html);
    const doc = dom.window.document;
    let ogTitle =
      doc.querySelector('meta[property="og:title"]')?.content || url;
    const ogImage = doc.querySelector('meta[property="og:image"]')?.content;
    return { ogTitle, ogImage, url };
  } catch (error) {
    console.error("Error fetching OG data:", error);
    return { ogTitle: "No title", ogImage: "No image", url };
  }

}

To get started quickly with this code, clone the repo, run `npm install` and `npm run dev`

nothing might show on the screen, why?

You need to create a `.env` file and have the following:

```bash
#### RPC for sepolia
PROVIDER_URL="https://rpc.sepolia.org"
CONTRACT_ADDRESS="your-contract-address"

Follow this article to get your contract ready and deployed.

This repo is just the frontend Dapp that interact with the smart contract using ether-js.